Pipeline pigs are used for many maintenance operations, such as inspections, and are often used while fluid is flowing through the pipeline. The pipeline pig generally has guides that extend out from a central body to keep the body centralized, and rubber rings or disks that engage the inner surface of the pipeline, which allows a pressure differential to move the pig through a pipeline. In some circumstances, it is necessary to insert the pig in a pipeline that has a larger diameter downstream of the injection point. In cases like this, it is necessary to allow the pig to expand in order to keep it centralized, and maintain the pressure differential. U.S. pre-grant publication no. 2001/0010104 (Couchman et al.) entitled “Pipeline Pigs” describes a pipeline pig with support elements that keep the pig centralized, and drive elements that engage the inner will of the pipelines. Both the support and the drive elements adapt to a range of pipeline diameters.